Honing machine



June 23, 1942. H. J. CALDWELL 2,287,0 85

HONING MACHINE Filed Sept. 29, 1959 3 Sheets-Sheet 1f nw :EL m hw ||I|||1l||l|u Illl. lllllllllllllll ll NvaNTocL/J w ww.. :--L weafihl @fa/v' Caf/dave f-M4 (ffl-neways June 23, 1942. H J, CALDWELL 2,287,085

HO'NING MACHINE Filed Sept. 29, 1939 3 Sheets-Sheet 2 Cf. (2a/dwg# NVENTOQL/ y @M ya m June 23, 1942. LL L CALDWELL 2,287,085

HONING MACHINE Filed Sept. 29, 1959 5l Shee'cs-Sheel 3' @d TTOmEy/S Q/a/g cyan/awe# ffm 1%. wm.

Patented June 23, 1942 i 'Harry- J; Caldwell, Rockford, Ill., assignor. to`

Barnes- Drill.. C., Rockford; ya.corporationY 0f. Illinois,

.Application september 29, 1939;,.seria1f-No.297,035.. 15,c1aims. (c1. 5'1"-3) The invention relates -to machines for dressingcylindrical surfacesand more-particularly to ma- Y chines .for dressing suchsurfaces` by a honingorlapping operation.

Honing and-lapping operations involve the-relative Arotation and simultaneous relative reciprocation of acylindricalabrasive tool or hone and the work piece, the rotational movement-being continuousin the honing.. operationandintermittent inthe lapping operation. The termv honing as-employed'herenafter is intencledto` embrace both operations. Y

The honing operation is used extensively iny dressing both internal" `and external isurfaces where a-high-de'gree'lof accuracy forfronndness and straightness-'and a-truesmooth surfaeeinsh is desired. While the operations arefundamentally-the same for both-types of Work, substanf tially differentoperating requirements arev in'- Volved'in holdingthe! tool andwork'- andv in ef-V fectingthenecessary-relative movements there between. For this reason itV has beenthe-practice heretofore -to provide separate machinesfior' each type of work.

One object of the presentinventionisto-provide a-honing machineof novel-andadvantageousconstruction which isuniversally applicable for- `honingeitherinternal orexternalsurfaces Afurther object is to provide a reciprocatoryl head or carriage and aguidewayA therefor particularly suitable` for horizontal honing machines and. embodying. novelfeatures of constructiony whichi facilitate the supporting ofA an elongated element such as a Work piece ontool driver-at one or. inorei` pointsintermediate its iends.- l

Other. objects and; advantages-of the inventioniwillbecoine apparent from the following-detaileddescrption of the preferred vembodiment'- illustrated` in f the.. accompanyingv drawings inv whiclng' Eigurel is a side elevational View of a-horizontal. honing machine: embodying the features ofY the,:,invention', the I machine. beingsetup forinternalzlioningz Fig. 2. is'a fragmentary side elevational'viewof the machine aszseti up1for externalfhoning.

Fig. Slis a-plan-Viewof the mainhead-or carriage.v of the machine..

Fig. Lisa transversev Vertical sectional-'view of the machine taken alongA the .line L11- 4 of; Figi 1.

li'g.` 5" is4 a detailedview of: the mechanism-for operatively connecting Vthe flexible traction mem.- bers withfthe .toolfheadtaken `along the line 5-5f. of Fig. 4. 'i'

Fig. 6. is a-vertical-sectional view ofrthe:re tractible workior. driverc'sup'porting 'xture? taken i alongt'he'linev SS-lfofEi'gJ. J

Fig.v .'T-isafragrnentary View of a-controllvalve andthe operatinglmeans. therefor.

8.15 a plan-.view-c'of-.the' auxiliary-header carriage-.of 'themachin'e...

Eig.' Slis. a schematic A'diag-ramV ofi the hydraulic circuiti showingV the'. arrangementziandi relationshiplofiv the operating, and'control elements of the'machine;

For; purposes; of: illustration, the invention -has beenlshown incorporatedin a machine for-honingrelativelyv .long .1 work; piecesfwhich. are?. mostir conveniernly4 supportedV in:.:a.. horizontal position, Themachine-'is equippedwith two reciprocablev tool heads. adapted to be coupled togetherforA reciprocation as a unit for honing certain types of Work'land;separable.to-allow one headtoreciprocate alone. forhoningsother. types. offwork. These comprise a-mainheadiH (Figsi 1L4)` adapted l. to carry` a V.convention-alinternal .'ho'ningtool T, .andanrauxiliaryheadH (Figs` 1;-2-and8`ladapted to carryan external-honingk tool ..T"a1soof conventional construction.- IThe heads are-v mounted. for reciprocation'ion a-g-uideway'of suf-Y rlcient length to :permit-the headsfwhen coupled,- to move throughra full stroke whereby. to-.traverse the tool from onefendofaf-Wo'rk-piece tothe other.v

Suitable power driven means, preferablyof the hydraulic type, is'1provided..forreciprocatingthe heads toleiect the relative reciprocatoryl movementsl ofthe honing tools and the Workpieces on which' theyare'- operating.- When. thef machine. is-used for-honing internal surfaces;- the' Work piece Ais stationarilysupported while the tool is rotated and?. recproc'a'tedf For this-pur pose, the toolhe'adgf are coupled together? forl reciprocation asaunit; the! auxiliary head H" in thiscase servingfmerelyto drivfe the main head H which-carries the tool-L For honing external surfaces,` one endof 'the workpiece-issupportedin-a chuck carriedE on 5r the rotating spindleof the mainhead wlfiille'the' other end of the work is rotatably supported on a center carried by a suitable tailstock removably mounted on the base of the machine. The main head H thus remains stationary at one end of the guideway while the tool is traversed over the work -by reciprocation of the auxiliary head or carriageH. In this instance, the work is rotated by the spindle driving means on the main tool head.

In the preferred form of the machine, the guideway for the reciprocatory heads is oifset laterally with respect to the base and the heads are constructed so as to overhang the base and thus aline properly with the work. The guideway can thus be made of suflicient length to accommodate both heads without one interfering with the other. It also leaves ample room within the base structure for mounting auxiliary supporting fixtures of the retractible type for supporting an elongated element which may be either the tool driver or the work piece at one or more intermediate points. In other words, the novel arrangement of the guideway materially facilitates the supporting of the element at the intermediate points. Moreover the exible traction members for reciprocating the heads may be located centrally of the guideway and secured to the heads in a manner such as to eliminate any tendency of the heads to twist upon the guideway.

Referring now to Figs. 1 and 2 of the drawings, the machine selected to illustrate the invention comprises generally a base consisting of a main section I I and an outboard section I2 bolted or otherwise rigidly secured together in end-to-end relation. The outboard base section serves in this instance as a stationary Work support for work to be honed internally by the tool T. For this purpose it is equipped with suitable work holders I3 for holding a work piece such as a hollow tube or cylinder W in a substantially horizontal position with its axis parallel to the guideway on which the head H reciprocates. An adjustable support and guide I4 is also mounted on the outboard section of the base for supporting the honing tool when withdrawn from the work and for guiding the tool into and out of the work.

As will be seen by reference to Fig. 4 the main base section II is of generally rectangular cross section and is provided adjacent its upper end with a rigid horizontal bed I5. Arranged in sideby-side relation with the base section II is an auxiliary base or frame I 6 the upper end of which projects substantially above the top of the main base section. The frame I6 may be of substantially the same length as the base section I I and its purpose is to support the guideway for the main head H and the auxiliary head H which carry the internal honing tool T and the external honing tool T', respectively. The guideway, as herein shown, comprises a pair of guide bars I9 mounted on the frame I6 in parallel spaced relation. Preferably these bars are mounted so thatthe plane ofthe guideway is inclined upwardly and outwardly from the bed I of the machine. Moreover, the inner bar of the pair is located substantially at the edge of the main base section so that the guideway, as a whole is offset laterally with respect to the base. This leaves the base entirely clear for mounting supporting xtures to be described hereinafter. The heads H and H' are supported on the guide bars by suitable roller members 20 in well known manner,

Referring more particularly to Figs. 3 and 4, the head H in its preferred form comprises a relatively short, rectangular pedestal 2| which may be constructed as a light weight metal casting. The roller members 20 are journaled on studs projecting from the lower end of the pedestal. Rigid with the upper end of the pedestal is a generally rectangular table 22 overhanging the bed I5. Journaled on the table 22 with its axis substantially parallel to the reciprocatory path of the head is a spindle 23 carrying on its outer end a chuck 24 of suitable and well known construction adapted to hold one end of a cylindrical element such as an elongated tubular tool driver 25 such as is employed for carrying the honing tool T or an elongated cylindrical work piece W to be honed externally.

Mounted on the table 22 of the main head H is a motor M arranged to rotate the spindle 23 through the medium of suitable gearing enclosed in a housing 26 which forms a part of the table. Rotation of the spindle may be utilized to drive either the external honing tool T (through the medium of the driver 25) or the work piece W'.

The auxiliary head H as shown in Fig. 8 is provided with a pedestal 2I similar in all respects to the pedestal 2I and carrying rollers 20 for supporting the head oh the guide bars I9. The upper end of the pedestal 2I terminates in a horizontally extending table portion 22 overhanging the bed I5 and equipped with a suitable fixture 21 for supporting the external honing tool T.

In the preferred form of the machine, the auxiliary head H is operatively connected with the head reciprocating mechanism which may be of any suitable character, and when the main head H is to be reciprocated, the two heads are coupled together for movement as a unit. To this end, the pedestal 2I' of the auxiliary head is formed with an elongated extension 28 adapted to project over the pedestal 2l of the main head when the heads are brought together as shown in Figs. l and 9. Machine bolts 29 threaded into the extension and the pedestal 2I of the main head rigidly connectl the heads together.

Thus, it will be noted that the auxiliary head H is reciprocated for either internal or external honing while the main head H is reciprocated only for internal honing. When the machine is set up for the latter type of honing, the tool T is removed from the auxiliary head to provide a clear passage for the tool driver 25, the bolts 29 are removed to free the auxiliary head for independent reciprocation and the main head H is moved to the rear end of the guideway to serve as a stationary support for one end of the work piece. As explained above, said one end of the work piece is held in the chuck 24. The other end of the work piece may be supported in any suitable manner as on a conical center 3l mounted on a tailstock 32. The tailstock may be of generally conventional construction preferably embodying the usual adjustable spindle 33 movable axially by means of a crank 34 to engage and disengage the center with the work. As the tailstock is used only when the machine is set up for external honing, it is preferably detachably secured in a suitable guideway 32 extending longitudinally of the bed plate I5 so that it can be easily adjusted for work pieces of dierent length and can be removed when the machine is to be used for internal honing.

In the exemplary machine, relative reciprocation of the tool and work is effected both for internal honingand. for `external honing by reciprocation ofi the head which carries the'tool. While any suitable power driven means may be utilized for. reciprocating the head, it is preferred to utilize pressureuid operated means for thispurpose because of itssmooth action and ease of control. Moreover, for reasons of economy, it is preferred to employ a single reciprocating mechanismarranged to actuate one or both of the tool .heads as required.

The reciprocating mechanism herein shown is ofwell. known constructioncomprising a power driven actuator in the form of a grooved cable drum. 4| (Figs. 1, 2 and 9) rotatably supported at one end of the. frame or extension i6. A.

sheave42 is rotatably supported atthe other end ofthe frame. Flexible.tractionmembers 43 and 44 suchV as wire cablesare operatively associated with the drum 4|, each cable. being anchored at one end' to the drum and extending therefrom below and generally parallel to the guideway. The other ends ofthe cables are connected together by a member arranged for detachable connectionf with the auxiliary head H'. As herein shown, each cable is anchored to a bracket 45 (Fig. 5) formed integrally with a flat, plate like member 46 adapted to be secured to the bottom wall of the pedestal 2|. In the presentinstance the cable 43 is'led directly from the members 46 tothe'cable drum while. thecable 44 is carried over the sheave 42. Thus when the drum is rotated in one direction the cable 43 is paid out and the cable 44 iswound up to move the head H forwardly on the guideway. When the direction of rotation of. the cable drum is reversed the cable 44 is paid out and the cable 43 is wound up to movethe head H back toward the rear end of the guideway.

To facilitate assembly of the machine elements, the members 46 is preferably secured to the head H by bolts 41 threading into the bottom wall of the pedestal 2l' thus operatively connecting the reciprocating mechanism vwith that head. A hat key 48 'seated in alined transverse grooves in the member and the pedestal locks the parts together and protects the bolts from excessive strains.

The cable. drum 4I may be rotated by a motor of any suitableA type such as a reversiblerotary uid motor FM. As shown in Fig. 9, the huid motoris drivingly connected with the drum in well known manner through the medium of a worm.5l and worm wheel 52. Pressure fluid is supplied to the fluid motor by a pump P through suitable hydraulic circuits including a reversing valve V of well known construction. An electric motor M drives the pump. The operation of the valve V is controlled by a pilot valve V operated by control mechanism which may be generall'y similar to that disclosed and claimed in my copending application Serial No. 267,572 filed April 13, 1939.

The control mechanism as herein shown, includes a control rod 6l extending generally parallel. to the guideway for the heads Hand H' and supported in brackets 62 on the side walls of the base section Il for limited rocking movement. Cam devices 93 adjustably mounted on the control rod are adapted to be engaged by a cam roller 64 carried on a laterally projecting arm 65 of the auxiliary head H'. 'I'he cam devices are set so that the engagement by the cam roller takes place. as the head approaches the ends. of its reciprocatory stroke whereby the control'. rod is rocked; between two limitpostions.

The rocking of. the. control. rod. serves `to .operate the pilot valve V asdescribed inthe prior application and thus vthrough the valve V` controls the direction of rotation ofthe motor, FM. and consequently the direction ofi movement of the head operatively connectedthereto. As the two head1)` are coupled together for internal honing, the cam roller (54 is operative to control reciprocation in both internal and externalhoning operations.

To attain a high degree of accuracy in honing relatively long workY pieces, it is essential that the rotating element, which may be either the work piece or the tool driver as above explained', be supported so as to avoid any perceptible sagging between the.- points of support. The machine in its preferred form is therefore equipped with one or more auxiliary supporting units for supporting the rotating element at a point or points intermediate its ends. These units are conveniently mounted on the bed plate l5 ofthe base section Il immediatelybelow the element to be supported. disclosed represent an improvement over supporting units disclosed and claimed in the copending application of A. M. Johnson, Serial No. 279,403, filed June 16, 1939, now Patent No. 2,245,922, granted June 17, 1941.

As clearly shown in Fig. 6, each supporting unit 'I9 comprises a hollow, general cylindrical frame il having a reduced end portion adapted to fit in an aperture 'IZinvthe-bed plate l5.Y The frame thus presents a shoulder i3 adapted to rest on the bed plate andthe entire-framestructure is rigidly secured thereto as bybolts lil. Where only one support isrequired, it is ordi narily installed approximatelyA at the center of the bed, If there are a plurality of supportsthey may be spacedapart appropriately as shown in Figs. 1 and 2.

Carried on the lower end of the frame 'Il is a closed cylinder I5 having a working piston 'f6 with a piston rod 'l projecting through -a suitable packing gland Tl at the upper end of the cylinder and into the enlarged upper portion of the frame. Later-ally extending pins 18- project from opposite sides of the piston rod and engage in vertical guide slots 19 formed in the sides of the frame to guide the piston rod for vertical reciprocation between thepositions shown in full and dotted lines in Fig. 6.

Pivotally mounted on the upper end of the piston rod Hare a pair of arms each carrying on its free end a roller 8l adaptedto engage the rotating `element when the piston rod is operated to its active position. The arms 89 are adapted to be moved toward or from each other to ad'- just the position of the rollers for elements of different diameter. For this purposean adjusting screw 82 having right and left hand screw threads at opposite ends for engagement with nuts 83 carried on the respective armsis rotatably anchored to an extension 84 of the piston rod as by opposed lock nuts 85. Accordingly, rov tation of the screw in one direction serves to open up the arms while the rotation in the opposite direction closes the arms together. In this way the rollers 8l may be accurately positioned so that when the piston rod TI is moved to its uppermost position the rollers engage and support the work in the desired straight, sagless condition.

The function ofthe hydraulic apparatus of the supporting unit isv to. raise the rollers 8| to active position to-.support-the rotating element and The supporting units herein to retract them within the upper portion of the frame I to vpermit the head I-I or H to pass in its reciprocation. For this purpose pressure uid is supplied to each of the cylinders 15 from the pump P through parallel hydraulic circuits containing individual control valve V-3 and V--4. These valves are of the reversing type, that is, each has a movable plunger operative in one position to direct pressure fluid into the lower end of the associated cylinder I5 and operative in the other position to direct pressure fluid into the upper end of the cylinder.

In order to coordinate the operation of the supporting units with the movements of the heads, means is provided whereby the valves V-3 and V--4 are operated incident to the reciprocation of the heads on the guideway. To facilitate such operation, the valves are preferably mounted on a top plate 86 running longitudinally along the top of the frame I6, each valve being located somewhat to the rear of the unit which it controls so as to allow ample time for retraction of the support. The plunger of each valve is provied at one end with an extension 9| projecting forwardly over the guideway and having at its outer end a vertical stud 93 on which is journaled a roller 92 adapted for engagement by a suitable cam or cams carried by the head H.

As herein shown, the cams provided for this purpose include a plate 94 having an upwardly opening cam slot 95 adapted to receive the rollers 92. The cam slot is shaped so that in the forward movement of the auxiliary head, the

valve plunger is moved inwardly or toward the right as viewed in Fig. 'l so as to direct pressure fluid into the upper end of the cylinder 'I5 and thus effect withdrawal of the work or driver supporting rollers from the path of the head.

On the return movement of the head, the valve is moved back to its original position to direct pressure fluid into the lower end of the cylinder and the supporting rollers are again raised to active position. A spring pressed detent D engaging in suitable notches in the extension 9| acts to hold the valve plunger in either set position.

When the head I-I is used alone for honing external surfaces, it is equipped with an additional cam plate 96 which may be conveniently mounted on the extension 23 of the auxiliary head and secured thereto by the screws 29 which serve to couple the heads together for internal honing. The plate 96 has a cam slot 98 disposed reversely to the cam slot 95. Due to the form of this cam slot the valve plungers are shifted into support raising position after the auxiliary head has passed the support. On the return movement of the head the cam slot accordingly sets the valves to lower the supports so that the head can pass while the cam slot 95 again initiates the elevation of the supports to active position. Thus, the work piece is adequately supported on both sides of the tool head so that the tendency to sag is e'lectually avoided and attendant vibration or whip is substantially eliminated.

When the machine is used for internal honing, the supporting units are retracted under control of the cam plate 94 to allow the coupled heads to pass in their movement toward the work. As the tool driver projects forwardly fromthe head H, there is no necessity of elevating the supports in the rear of the head. Accordingly, the cam plate 95 is removed from the machine for this type of honing and the supports remain in retracted position until the heads pass through in their return movement.

In setting up the machine for internal honing, the cam plate 96 is removed from the extension 28 of' the auxiliary head and that head is rigidly coupled to the main head by means of the bolts 29. The tool driver 25 carrying the internal honing tool T is then secured in the chuck 24 of the main head spindle 23. It will be understood, of course, that the external honing tool T is removed from its socket in the head I-I to provide a passage for the driver. The tailstock 32 is replaced by the tool support and guide I4 and the work piece W is then mounted on the fixtures |3 adjacent the guide.

The honing cycle is now initiated in well known manner by starting the driving motors M and M and opening the starting valve V5 in the pressure fluid line from the pump P to the fluid motor FM. The latter turns the drum 4| to wind up the cable 44 and move the coupled heads toward the work, the tool entering the same just before the cam roller 64 engages the rear cam 63 of the control rod. Forward movement of the heads continue until the tool is traversed entirely through the work and then the heads reverse due to engagement of the front cam 63 by the roller 64 and the resultant reversal ofthe fluid motor. During the honing operation, the cam plate 94 coacts with the valves V3 and V4 to effect the retraction of the supports 'I0 in succession as the heads advance and to initiate the successive elevation of the supports as the heads return. This cycle of operations is repeated at each end of the stroke until the work is finished to the desired dimensions and the machine stopped either manually or by a suitable automatic controller. i

To change the machine over for external honing, the bolts 29 are removed to uncouple the heads and the cam plate 96 is secured in place on the extension 28 of the auxiliary head H. External honing tool T is secured in its socket and the driver 25 is removed from the chuck 24, the main head being moved to the rear of the guideway as shown in Fig. 2. After the tool support and guide I4 has been replaced by the tailstock 32, the work piece W' may be inserted through the tool T and secured between the center 3| and the chuck 24,

The honing cycle is started in the manner above explained but in this case, only the auxiliary head H' is reciprocated to traverse the tool T from one end of the work piece to the other. Motor M drives the main head spindle and thus rotates the work relative to the tool which is non-rotatably supported on the auxiliary head. Reciprocation is controlled by the cam roller 64 coacting with the cams 63 of the control rod as above explained.

In the advance of the head H', the cam plate 94 initiates the retraction of the supports 10, in succession as in the previous case to allow the head to pass. Cam plate 96 reoperates the valves V3 and V4 to raise the supports after the head has passed so that the work is supported against sagging on either side of the head. On the return movement of the head the operation of the cams is reversed, cam 96 initiating the retractions of the supports while cam 94 causes them to be raised after the passage of the head.

It will be apparent from the foregoing that the invention provides an improved honing machine embodying novel features of construction which make it universally adaptable for honing either internal or external cylindrical surfaces.` The -machine-is'equipped with two separate heads one :of .which'maybe recipro'cated independentlyor coupled to .the otherheadto act as adriver :for the same. 'Said one head is adapted'to carryra non-rotating yhoning tool such as an external honeandthe otherhead is adapted to carry a vrotating'tool such as aninternal hone. The latter head additionally is capable of serving as a sup- `portfor the work operated on by the tool carried Vby the first mentioned head. The heads Vare mounted on a gudeway which, by reason of its novel-location with respect to the main baserseotion of the machine leaves that section 'free for theinstallations of auxiliary equipment such as a Work or driver supporting unit having a member niovable in a path substantially perpendicular to the axisof the gudeway. This greatly simplifies the problem of supporting elongated elements of this character to prevent sagging intermediate the ends thereof.

I claim as my invention:

A1.In a machine for honing internal or oxternal surfaces of elongated work pieces, the combination of a base consisting of a main section and an outboard section, a gudeway extending generally parallel to the main base section, a pair of heads mounted for reciprocation on said guide- Way, power driven reciprocating means operatively connected with one of said heads, means on said one head for carrying Vexternal honing tool, a rotatable spindle on the other head having a chuck adapted to hold either an elongatedl driver for an internal honing tool or one end of a work piece to be operated on by the external honing tool, means for coupling Y said heads together for reciprocation as a unit, means on said outboard base section for holding a work piecerin position to be operated on by the lnternallhoning tool, both of said heads being reciprocated to traverse the internal honing tool over the work, and a tail stock adapted to be detachably mounted on the main base .section for cooperation with the chuck`carriedby the spin--l dle of said other head for holding and rotating awork piece to be operated onby the external honing, said one head being reciprocated Vto traverse the tool over the workpiece in -such operation.

2. In a horizontal rhoning machine, in combination, an elongated base consisting of a main section and an outboardsection arranged in endto-end relation, means on the outboard base section for supporting an elongated work piece in a generally horizontal position, a frame rigidly secured to one side of the main base section, said frame projecting substantially above the top of the main section, spaced parallel guide bars mounted on the projecting portion of said frame to form a gudeway extending generally parallel to the axis of the work piece, and a head mounted for reciprocation on said gudeway, said head having a portion overhanging said main base section, and a tool carrying spindle journaled in said overhanging portion of the head in axial alinement with the work piece.

3. In a machine for honing internal or external surfaces of elongated work pieces, the combination of a base consisting of a main section and an outboard section, a gudeway extending generally parallel to the main base section, a pair of heads mounted for reciprocation on said gudeway, a rotatable spindle on one of said heads, a chuck on said spindle adapted to carry an elongated honing tool driver, means on the other of said heads for carrying an external honing tool, power driven. means for .reciprocating said other head, means for coupling said heads togetheriorreciprocation asa unit, means on the outboard base section for holding a work piece to be operated on `by the internal honing tool carried bysaid .one head,.and means inciudin'gsaid oneliead for holding a work .piece tobe .operated kon by .the .external honing 'tool carried; by Vsaid `other "head,

.4. In a machine /for honing internal or external cylindrical surfaces, Ythe combination 'of an elongated frame, aguideway extending longitudinally of said frame, a pair of heads mounted for reciprocation on said gudeway, means on one of said heads for'holding an external honing tool,.means on the other head for holding an internal tool, .reciprocating means common to said heads including a cable drum rotatably supported at one end of said frame, power driven means for rotating said-drum'rst in one direcf tion and then in the other direction, a pair of flexible cables anchored `to vsaid drum andextending from opposite sides thereof, means connecting said cables with said one head, and means for coupling said heads'together for reciprocation as a unit,

5. In a machine for honing internal or ex ternal surfaces, the combination of a gudeway, an internal honingtool'supportingV head mounted for reciprocation on said gudeway, Yan external honing tool supporting head mounted on said gudeway,V said vheads'being reciprocable on the gudeway, pressure fluid operated head reciprocating means, means including a pair of exible traction members operatively connecting said reciprocating means with-one of said vheads, and means for coupling said heads together for reciprocation as a unit.

6. In a machine for honing internal or external surfaces, the combinationof a gudeway, aninternalhoning tool supporting head mounted for reciprocationfon said gudeway, an'external honing tool supporting head mounted'on said gudeway, saidheads being reciprocable on the gudeway, power driven head reciprocating means, means operatively connecting said reciprocating means, with one of said heads, and coupling means for securing said one head to theother headto -operatively associate lthe latter head with said reciprocatingmeans.

7. A honing'machine-having, in combination, a gui'deway,raheadmounted rfor reciprocation on the gudeway, supportingmeans carried by vsaid head for holding one type of honing tool, a second head mounted for reciprocation on the guide- Way, supporting means carried by said head for holding a different type of honing tool, power driven means in operative association with one of said heads for independently reciprocating the head on the gudeway, and means for coupling said heads together for reciprocation as a unit.

8. A horizontal honing machine having, in combination, a gudeway, a head mounted for reciprocation on the gudeway, supporting means carried by the head for holding one type of honing tool, a second head mounted for reciprocation on the gudeway, means carried by said second head for holding a different type of honing tool, means for reciprocating one of said heads independently of the other including a power driven actuator, a pair of flexible cables operatively associated with said actuator and extending below and generally parallel to the guideway, a member connecting the ends of said cables and arranged for detachable connection with said one head, and means for coupling said one head with the other head to reciprocate the latter.

9. In a horizontal honing machine, in combination, a base, an elongated element supported at opposite ends in a substantially horizontal position above the base, means for rotating said element, means for supporting said elementat an intermediate point comprising a piston supported on the base below said member for movement toward and from the same, a piston rod projecting upwardly from said piston, a pair of arms pivoted on said rod, a roller on each of said arms for engaging and supporting said element, and means for rocking said arms about their pivots to adjust the position of said rollers for accommodating elements of different diameters.

10. A retractible supporting unit comprising, in combination, a hollow cylindrical frame, a cylinder secured to the lower end of said frame, a piston operating in said cylinder, a piston rod projecting upwardly from the piston through said frame, said piston rod having a supporting device upon its upper end, means for guiding the piston rod in its movement comprising a bar extending transversely through the piston rod and projecting on opposite sides thereof, and parallel channels in said frame for receiving the ends oi said bar.

11. In a horizontal honing machine, in combination, an elongated base, a frame located at one side of said base, a guideway on said frame, a pair of heads mounted on the guideway, supporting means carried by each head for holding a honing tool over said base, power driven means for reciprocating one or both of said heads, a second guideway on said base, and work supporting means mounted on said second guideway comprising a headstock having a center disposed substantially in axial alinement with the tool holding means carried by said heads.

12. A honing machine having, in combination, a guideway, a head mounted for reciprocation on the guideway, supporting means carried by said head for holding one type of honing tool, a second head mounted for reciprocation on the guideway, supporting means carried by said second head for holding a different type of honing tool substantially in axial alinement with the tool held by said first head, and common power driven means for reciprocating said heads.

13. A honing machine having, in combination, a guideway, a head mounted for reciprocation on the guideway, supporting means carried by said head for holding an external honing tool, a second head mounted for reciprocation on the guideway, a spindle journaled on said second head substantially in axial alinement with the tool carried by said rst head and adapted to carry an internal honing tool, and power driven means operable to drive one of said heads individually or both of said heads simultaneously.

14. A horizontal honing machine having, in combination, an elongated base, means on said base for supporting a cylindrical work piece at opposite ends, a head arranged to carry a honing tool of the type adapted to encircle the work piece, a frame located at one side of the base to leave the latter unobstructed, a guideway on the frame supporting said head for reciprocation in a path substantially parallel to the axis of the work piece, power driven means for reciprocating the head on the guideway for traversing the tool longitudinally of the work piece, and auxiliary work supporting means mounted on said base, said supporting means including a work engaging member movable in a path substantially perpendicular to the axis of the work piece to allow the tool to pass when the head is reciprocated.

15. In a machine for dressing elongated cylindrical work pieces, the combination of an elongated base, means on the base for supporting the work piece at opposite ends, a head arranged to carry an abrasive tool of the type adapted to encircle the work piece, a frame located at one side of the base, a guideway on the frame supporting said head for reciprocation in a path substantially parallel to the axis of the work piece, power driven means for reciprocating the head on the guideway for traversing the tool longitudinally of the work piece, auxiliary work supporting means including a member mounted on said base for movement transversely of the work piece, power actuated means operative to hold said member in an advanced position to engage and support the work piece at a point intermediate the ends thereof, and control means for said power actuated means operative to effect periodic withdrawals of said member to allow the tool to pass as the head is reciprocated.

HARRY J. CALDWELL. 

